C#连接本地.mdf文件：项目中右键点击，新增——数据——基于服务的数据库，项目下直接生成.mdf数据库文件，后台(数据库的写入用参数传递)：

namespace ADO.NET
{
    class Program
    {
        static void Main(string[] args)
        {
            //SQLServer 附加mdf文件
            string dataDir = AppDomain.CurrentDomain.BaseDirectory;
            if (dataDir.EndsWith(@\"\\bin\\Debug\\\") || dataDir.EndsWith(@\"\\bin\\Release\\\"))
            {
                dataDir = System.IO.Directory.GetParent(dataDir).Parent.Parent.FullName;
                AppDomain.CurrentDomain.SetData(\"DataDirectory\", dataDir);
            }
            using (SqlConnection conn = new SqlConnection(@\"Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\Database1.mdf;Integrated Security=True;User Instance=True\"))
            {
                conn.Open();
                //写入一条数据
                string strUserName = \"作业本\";
                string strPWD = \"Ab123456\";

                using (SqlCommand sqlCmd = conn.CreateCommand())
                {
                    sqlCmd.CommandText = \"insert into Mytable1(Name,Password) values (@UserName,@PWD) \";//连接字符串进行参数化
                    SqlParameter[] sqlPara = new SqlParameter[] {
                    new SqlParameter(\"UserName\",strUserName),
                    new SqlParameter(\"PWD\",strPWD)
                    };
                    sqlCmd.Parameters.AddRange(sqlPara); //把Paramerter 数组参数添加到sqlCmd中
                    sqlCmd.ExecuteNonQuery();
                    Console.WriteLine(\"Insert OK\");
                }

                //从表中读取数据
                string strRead = \"SELECT   ID, Name, Password FROM      MyTable1 \";
                using (SqlCommand sqlCmd = new SqlCommand(strRead, conn))
                {
                    //sqlDataReader 逐行读取数据
                    using (SqlDataReader sdr = sqlCmd.ExecuteReader())
                    {
                        while (sdr.Read())
                        {

                            int id = sdr.GetInt32(sdr.GetOrdinal(\"ID\"));  //sdr.GetOrdinal 获取列的序号
                            string Name = sdr.GetString(sdr.GetOrdinal(\"Name\"));
                            bool PWD = sdr.IsDBNull(sdr.GetOrdinal(\"Password\"));
                            Console.WriteLine(\"ID:{0},Name:{1},PWD：{2}\", id, Name, PWD);
                            Console.WriteLine(sdr.GetString(1));
                        }
                    }
                }
                conn.Close();//此处可以省略，Dispose()方法会自动检查
            }
        }
    }
}